This invention relates generally to the art of irrigation systems, and more specifically concerns a corner watering system addition for a center pivot irrigation system.
Center pivot systems are being increasingly used to irrigate large sections of land. Typically, such systems are capable of watering a quarter section of land, i.e. 160 acres. A center pivot irrigation system generally comprises a long primary, or center, pivot boom, which includes a water conduit and a supporting truss arrangement. The center pivot boom is divided into a plurality of sections, each one of which pivot relative to its adjacent sections. The center pivot boom is supported by a plurality of wheeled towers, located at spaced intervals along the length of the center pivot boom, typically in the vicinity of the pivot points linking the sections, i.e. near the ends of the sections.
Sprinklers are located at spaced intervals along the length of the water conduit. The entire center pivot boom is moved about the center pivot point through movement of its wheeled towers, which are individually powered by motors, so that a circular pattern of water coverage is developed about the central pivot point.
The primary problem with such center pivot systems, however, is the lack of complete coverage of a given parcel of land, as the outline of the water coverage of such a system is a circle, while most land parcels are square or have a straight line outline. Hence, significant portions of a given section of land irrigated by a center pivot system are virtually lost to productive use. As an example, on a quarter section of land in which water from a center pivot system reaches to the edge of the section boundary at points intermediate of each of the section's sides, approximately 20 percent of the land in the section, in particular, the corner areas, is not irrigated.
In order to overcome this problem, corner systems have been developed which extend from the end of the center pivot boom to water the corners of the sections. In one simple system, a sprinkler gun is used at the end of the center pivot boom. The resulting improvement is not, however, satisfactory. In another system, the center pivot boom stops on the diagonal, and a corner boom then swings out to cover a portion of the corner. This significantly improves the coverage of the system but delays the overall watering cycle significantly, however, which is undesirable.
It is thus desirable that the center pivot boom move at its normal rate while the corner coverage system is functioning, but it is important to the proper operation of such a system that the position of the corner boom, particularly its end point, be known at all times, to maintain proper control of the corner boom relative to the movement of the center pivot boom. Presently, however, it is difficult to accurately ascertain the location of the corner boom, due to the skewed configuration of the center pivot boom while it is in operation.
One solution to this problem concerning the location of the corner boom, particularly its end point, is to have the boom follow a buried conductor, such as shown in U.S. Pat. No. 3,902,668 to Daugherty, et al. However, the apparatus disclosed in that patent is relatively expensive and the buried conductor is subject to accidental damage from conventional farm machinery, as well as rodents, etc. Also, if the corner boom for any reason strays from contact with the buried conductor, it is difficult and time-consuming to re-establish communication.
Accordingly, it is a general object of the present invention to provide a corner watering system which is useful with a center pivot watering system to overcome one or more of the disadvantages of the prior art noted above.
It is another object of the present invention to provide such a corner system which is capable of covering a significant portion of the corner areas of a square section of land not otherwise reached by a center pivot system.
It is an additional object of the present invention to provide such a corner system which is capable of being controlled to such an extent that it can follow an irregular pattern, such as in order to avoid fixed objects.
It is a further object of the present invention to provide such a corner system which is capable of precisely locating the end point of a movable corner boom.
It is yet another object of the present invention to provide such a corner system which takes into account the irregular configuration of the center pivot boom in locating the end of the corner boom.